Hi, as per the fitment note for this fender, it is designed to fit the Mustang Shelby GT500. There are only 2 different part numbers for a front right fender for a 2013 Mustang: AR3Z16005A fits base models without pony package; the Boss 302 package; and the.GT without the BOSS 302 package but with the sport appearance package. AR3Z16005B fits base models with the pony package; GT models without the BOSS 302 package and without the sport appearance package; and Shelby GT500 models. The pony package is a trim level. If you are unsure if your car has it, we suggest that you contact an authorized dealer to help make that determination.